Production of adipic acid and derivatives from carbohydrate-containing materials

ABSTRACT

The present invention generally relates to processes for the chemocatalytic conversion of a glucose source to an adipic acid product. The present invention includes processes for the conversion of glucose to an adipic acid product via glucaric acid or derivatives thereof. The present invention also includes processes comprising catalytic oxidation of glucose to glucaric acid or derivative thereof and processes comprising the catalytic hydrodeoxygenation of glucaric acid or derivatives thereof to an adipic acid product. The present invention also includes products produced from adipic acid product and processes for the production thereof from such adipic acid product.

REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. provisional application Ser. No.61/268,414, filed Jun. 13, 2009, and U.S. provisional application Ser.No. 61/311,190, filed Mar. 5, 2010, the entire disclosures of which areincorporated herein by reference.

FIELD OF THE INVENTION

The present invention generally relates to processes for thechemocatalytic conversion of a glucose source to an adipic acid product.The present invention includes processes for the conversion of glucoseto an adipic acid product via glucaric acid or derivatives thereof. Thepresent invention also includes processes comprising the catalyticoxidation of glucose to glucaric acid and catalytic hydrodeoxygenationof glucaric acid or derivatives thereof to an adipic acid product. Thepresent invention also relates to processes for the preparation ofindustrial chemicals such as adiponitrile, hexamethylene diamine,caprolactam, caprolactone, 1,6-hexanediol, adipate esters, polyamides(e.g., nylons) and polyesters from an adipic acid product obtained fromprocesses which include the catalytic hydrodeoxygenation of glucaricacid or derivatives thereof.

BACKGROUND OF THE INVENTION

Crude oil is currently the source of most commodity and specialtyorganic chemicals. Many of these chemicals are employed in themanufacture of polymers and other materials. Examples include ethylene,propylene, styrene, bisphenol A, terephthalic acid, adipic acid,caprolactam, hexamethylene diamine, adiponitrile, caprolactone, acrylicacid, acrylonitrile, 1,6-hexanediol, 1,3-propanediol, and others. Crudeoil is first refined into hydrocarbon intermediates such as ethylene,propylene, benzene, and cyclohexane. These hydrocarbon intermediates arethen typically selectively oxidized using various processes to producethe desired chemical. For example, crude oil is refined into cyclohexanewhich is then selectively oxidized to “KA oil” which is then furtheroxidized for the production of adipic acid, an important industrialmonomer used for the production of nylon 6,6. Many known processes areemployed industrially to produce these petrochemicals from precursorsfound in crude oil. For example, see Ullmann's Encyclopedia ofIndustrial Chemistry, Wiley 2009 (7th edition), which is incorporatedherein by reference.

For many years there has been an interest in using biorenewablematerials as a feedstock to replace or supplement crude oil. See, forexample, Klass, Biomass for Renewable Energy, Fuels, and Chemicals,Academic Press, 1998, which is incorporated herein by reference.Moreover, there have been efforts to produce adipic acid from renewableresources using processes involving a combination of biocatalytic andchemocatalytic processes. See, for example, “Benzene-Free Synthesis ofAdipic Acid”, Frost et al. Biotechnol. Prog. 2002, Vol. 18, pp. 201-211,and U.S. Pat. Nos. 4,400,468, and 5,487,987.

One of the major challenges for converting biorenewable resources suchas carbohydrates (e.g. glucose derived from starch, cellulose orsucrose) to current commodity and specialty chemicals is the selectiveremoval of oxygen atoms from the carbohydrate. Approaches are known forconverting carbon-oxygen single bonds to carbon-hydrogen bonds. See, forexample: U.S. Pat. No. 5,516,960; U.S. Patent App. Pub. US2007/0215484and Japanese Patent No. 78,144,506. Each of these known approachessuffers from various limitations and we believe that, currently, none ofsuch methods are used industrially for the manufacture of specialty orindustrial chemicals.

Thus, there remains a need for new, industrially scalable methods forthe selective and commercially-meaningful conversion of carbon-oxygensingle bonds to carbon-hydrogen bonds, especially as applied inconnection with the production of chemicals from polyhydroxyl-containingsubstrates (e.g., glucaric acid), and especially for the production ofchemicals from polyhydroxyl-containing biorenewable materials (e.g.,glucose derived from starch, cellulose or sucrose) to important chemicalintermediates such as adipic acid.

SUMMARY OF THE INVENTION

Briefly, therefore, the present invention is directed to processes forpreparing an adipic acid product from polyhydroxyl-containingbiorenewable materials. In accordance with one embodiment, a process forproducing an adipic acid product from a glucose source is provided whichcomprises converting by chemocatalytic means at least a portion of theglucose source to the adipic acid product.

In accordance with another embodiment, the process for preparing anadipic acid product comprises reacting, in the presence of ahydrodeoxygenation catalyst and a halogen source, a hydrodeoxygenationsubstrate and hydrogen to convert at least a portion of thehydrodeoxygenation substrate to an adipic acid product, wherein thehydrodeoxygenation substrate comprises a compound of formula I

wherein X is independently hydroxyl, oxo, halo, acyloxy or hydrogenprovided that at least one X is not hydrogen and R¹ is independently asalt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl; ora mono- or di-lactone thereof.

In accordance with another embodiment, the process for preparing anadipic acid product comprises converting at least a portion of a glucosesource to a hydrodeoxygenation substrate comprising glucaric acid orderivative thereof, and converting at least a portion of the glucaricacid or derivative to an adipic acid product.

The present invention is further directed to processes for preparingglucaric acid. In one embodiment, the process comprises reacting glucosewith a source of oxygen in the presence of an oxidation catalyst and inthe substantial absence of added base.

The present invention is further directed to processes for preparingglucaric acid by reacting glucose with oxygen in the presence of anoxidation catalyst, wherein at least a portion of the glucose issolubilized with a weak carboxylic acid, preferably acetic acid.

The present invention is further directed to processes for thepreparation of industrial chemicals such as adiponitrile, hexamethylenediamine, caprolactam, caprolactone, 1,6-hexanediol, adipate esters,polyamides (e.g., nylons) and polyesters from an adipic acid productobtained from processes for the chemocatalytic conversion of a glucosesource, which may include, for example, the catalytic hydrodeoxygenationof glucaric acid or derivatives thereof.

The present invention is further directed to adipic acid product,polyamides, polyesters and caprolactam produced at least in part fromadipic acid product produced by the hydrodeoxygenation of ahydrodeoxygenation substrate, and, more particularly, from glucaric acidor derivative thereof.

Other objects and features will become apparent and/or will be pointedout hereinafter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the present invention, applicants disclose processesfor the chemocatalytic conversion of a glucose source to an adipic acidproduct.

Further, in accordance with the present invention, applicants discloseprocesses for the catalytic hydrodeoxygenation of a hydrodeoxygenationsubstrate comprising glucaric acid and/or derivatives thereof to anadipic acid product. The catalytic hydrodeoxygenation includes reacting,in the presence of a hydrodeoxygenation catalyst (i.e., catalystsuitable for the hydrodeoxygenation reaction) and a halogen source, ahydrodeoxygenation substrate and hydrogen to convert at least a portionof the hydrodeoxygenation substrate to an adipic acid product. Thehydrodeoxygenation catalyst of the present invention comprises a d-blockmetal (i.e., transition metal; groups 3-12 of the periodic table) and ishydroxyl, halo, oxo or acyloxy selective, more typicallyhydroxyl-selective, which increases yield and improves processeconomics.

The present invention also relates to processes for the catalyticproduction of glucaric acid from glucose. The process includes reactingglucose with oxygen in the presence of an oxidation catalyst and in thesubstantial absence of added base, wherein at least 50% of the glucoseis converted to glucaric acid. Conducting the oxidation reaction in thesubstantial absence of added base facilitates product recovery andimproves process economics. Further, this reaction can be conducted inthe presence of a weak carboxylic acid, such as acetic acid, in which atleast a portion of the glucose is solubilized. Moreover, preferredoxidation catalysts and/or oxidation reaction conditions provide yieldsof glucaric acid in excess of 60%, and up to 65% or more.

In another aspect of the invention, an adipic acid product prepared inaccordance with the disclosed processes may be converted, according toprocesses known in the art, to various other industrially significantchemicals including, for example, adiponitrile, caprolactam,caprolactone, hexamethylene diamine, 1,6-hexanediol, adipate esters,polyamides (e.g., nylon) or polyesters. Thus, adiponitrile, caprolactam,caprolactone, hexamethylene diamine, 1,6-hexanediol, adipate esters,polyamides (e.g., nylon) and polyesters may be prepared from glucosederived from biorenewable sources.

I. Feedstocks

Glucose can be obtained from various carbohydrate-containing sourcesincluding conventional biorenewable sources such as corn grain (maize),wheat, potato, cassava and rice as well as alternative sources such asenergy crops, plant biomass, agricultural wastes, forestry residues,sugar processing residues and plant-derived household wastes. Moregenerally, biorenewable sources that may be used in accordance with thepresent invention include any renewable organic matter that includes asource of carbohydrates such as, for example, switch grass, miscanthus,trees (hardwood and softwood), vegetation, and crop residues (e.g.,bagasse and corn stover). Other sources can include, for example, wastematerials (e.g., spent paper, green waste, municipal waste, etc.).Carbohydrates such as glucose may be isolated from biorenewablematerials using methods that are known in the art. See, for example,Centi and van Santen, Catalysis for Renewables, Wiley-VCH, Weinheim2007; Kamm, Gruber and Kamm, Biorefineries-Industrial Processes andProducts, Wiley-VCH, Weinheim 2006; Shang-Tian Yang, Bioprocessing forValue-Added Products from Renewable Resources New Technologies andApplications, Elsevier B. V. 2007; Furia, Starch in the Food Industry,Chapter 8, CRC Handbook of Food Additives 2^(nd) Edition CRC Press,1973. See also chapters devoted to Starch, Sugar and Syrups withinKirk-Othmer Encyclopedia of Chemical Technology 5^(th) Edition, JohnWiley and Sons 2001. Also, processes to convert starch to glucose areknown in the art, see, for example, Schenck, “Glucose and Glucosecontaining Syrups” in Ullmann's Encyclopedia of Industrial Chemistry,Wiley-VCH 2009. Furthermore, methods to convert cellulose to glucose areknown in the art, see, for example, Centi and van Santen, Catalysis forRenewables, Wiley-VCH, Weinheim 2007; Kamm, Gruber and Kamm,Biorefineries-Industrial Processes and Products, Wiley-VCH, Weinheim2006; Shang-Tian Yang, Bioprocessing for Value-Added Products fromRenewable Resources New Technologies and Applications, Elsevier B. V.2007.

II. Preparation of Glucaric Acid

In accordance with the present invention, glucose is converted to, forexample, glucaric acid. The preparation of glucaric acid can be effectedwith glucose using oxidation methods that are generally known in theart. See, for example, U.S. Pat. No. 2,472,168, which illustrates amethod for the preparation of glucaric acid from glucose using aplatinum catalyst in the presence of oxygen and a base. Further examplesof the preparation of glucaric acid from glucose using a platinumcatalyst in the presence of oxygen and a base are illustrated in theJournal of Catalysis Vol. 67, p. 1-13, and p. 14-20 (1981). Otheroxidation methods may also be employed, see for example, U.S. Pat. Nos.6,049,004, 5,599,977, and 6,498,269, WO 2008/021054 and J. Chem.Technol. Biotechnol. Vol. 76, p. 186-190 (2001); J. Agr. Food Chem. Vol.1, p. 779-783 (1953); J. Carbohydrate Chem. Vol. 21, p. 65-77 (2002);Carbohydrate Res. Vol. 337, p. 1059-1063 (2002); Carbohydrate Res. 336,p. 75-78 (2001); Carbohydrate Res. Vol. 330, p. 21-29 (2001). However,these processes suffer from economic shortcomings resulting from, amongother matters, process yield limitations and the requirement foradditional reaction constituents.

Applicants have discovered that glucose may be converted to glucaricacid in high yield by reacting glucose with oxygen (as used herein,oxygen can be supplied to the reaction as air, oxygen-enriched air,oxygen alone, or oxygen with other constituents substantially inert tothe reaction) in the presence of an oxidation catalyst and in theabsence of added base according to the following reaction:

Surprisingly, conducting the oxidation reaction in the absence of addedbase and in accordance with the reaction conditions set forth herein,does not lead to significant catalyst poisoning effects and catalystoxidation selectivity is maintained. In fact, catalytic selectivity canbe maintained to attain glucaric acid yield in excess of 50%, even 60%and, in some instances, attain yields in excess of 65% or higher. Theabsence of added base advantageously facilitates separation andisolation of the glucaric acid, thereby providing a process that is moreamenable to industrial application, and improves overall processeconomics by eliminating a reaction constituent. The “absence of addedbase” as used herein means that base, if present (for example, as aconstituent of a feedstock), is present in a concentration which hasessentially no effect on the efficacy of the reaction; i.e., theoxidation reaction is being conducted essentially free of added base. Ithas also been discovered that this oxidation reaction can also beconducted in the presence of a weak carboxylic acid, such as aceticacid, in which glucose is soluble. The term “weak carboxylic acid” asused herein means any unsubstituted or substituted carboxylic acidhaving a pKa of at least about 3.5, more preferably at least about 4.5and, more particularly, is selected from among unsubstituted acids suchas acetic acid, propionic acid or butyric acid, or mixtures thereof.

It has been further discovered that conducting the oxidation reactionunder increased oxygen partial pressures and/or higher oxidationreaction mixture temperatures tends to increase the yield of glucaricacid when the reaction is conducted in the substantial absence of addedbase.

In these and various other embodiments, the initial pH of the reactionmixture is no greater than about 7, and typically is less than 7 suchas, for example, 6 or less when a weak carboxylic acid is used tosolubilize at least a portion of the glucose. In accordance with thepresent invention, the initial pH of the reaction mixture is the pH ofthe reaction mixture prior to contact with oxygen in the presence of anoxidation catalyst. It is expected that the pH of the reaction mixtureafter oxygen contact will vary as the reaction proceeds. It is believedthat as the concentration of the glucaric acid increases (as thereaction proceeds) the pH will decrease from the initial pH.

Another advantage of the present invention is the essential absence ofnitrogen as an active reaction constituent. Typically, nitrogen isemployed in known processes as an oxidant such as in the form ofnitrate, in many instances as nitric acid. The use of nitrogen in a formin which it is an active reaction constituent, such as nitrate or nitricacid, results in the need for NO_(x) abatement technology and acidregeneration technology, both of which add significant cost to theproduction of glucaric acid from these known processes, as well asproviding a corrosive environment which may deleteriously affect theequipment used to carry out the process. By contrast, for example, inthe event air or oxygen-enriched air is used in the oxidation reactionof the present invention as the source of oxygen, the nitrogen isessentially an inactive or inert constituent. Thus, for example, inaccordance with the present invention, an oxidation reaction employingair or oxygen-enriched air is a reaction conducted essentially free ofnitrogen in a form in which it would be an active reaction constituent.

Generally, the temperature of the oxidation reaction mixture is at leastabout 40° C., more typically 60° C., or higher. In various embodiments,the temperature of the oxidation reaction mixture is from about 40° C.to about 150° C., from about 60° C. to about 150° C., from about 70° C.to about 150° C., from about 70° C. to about 140° C., or from about 80°C. or about 120° C.

Typically, the partial pressure of oxygen is at least about 15 poundsper square inch absolute (psia) (104 kPa), at least about 25 psia (172kPa), at least about 40 psia (276 kPa), or at least about 60 psia (414kPa). In various embodiments, the partial pressure of oxygen is up toabout 1000 psia (6895 kPa), or more typically in the range of from about15 psia (104 kPa) to about 500 psia (3447 kPa).

The oxidation reaction is typically conducted in the presence of asolvent to glucose. Solvents suitable for the oxidation reaction includewater and weak carboxylic acids such as acetic acid. Utilization of weakcarboxylic acid as a solvent adds cost to the process which cost, as apractical matter, must be balanced against any benefits derived from theuse thereof. Thus, suitable solvents for the present invention includewater, mixtures of water and weak carboxylic acid, or weak carboxylicacid.

In general, the oxidation reaction can be conducted in a batch,semi-batch, or continuous reactor design using fixed bed reactors,trickle bed reactors, slurry phase reactors, moving bed reactors, or anyother design that allows for heterogeneous catalytic reactions. Examplesof reactors can be seen in Chemical Process Equipment—Selection andDesign, Couper et al., Elsevier 1990, which is incorporated herein byreference. It should be understood that glucose, oxygen, any solvent,and the oxidation catalyst may be introduced into a suitable reactorseparately or in various combinations.

Catalysts suitable for the oxidation reaction (“oxidation catalyst”)include heterogeneous catalysts, including solid-phase catalystscomprising one or more supported or unsupported metals. In variousembodiments, metal is present at a surface of a support (i.e., at one ormore surfaces, external or internal). Typically, metal is selected fromthe group consisting of palladium, platinum, and combinations thereof.Additional other metals may be present, including one or more d-blockmetals, alone or in combination with one or more rare earth metals (e.g.lanthanides), alone or in combination with one or more main group metals(e.g. Al, Ga, Tl, In, Sn, Pb or Bi). In general, the metals may bepresent in various forms (e.g., elemental, metal oxide, metalhydroxides, metal ions, etc.). Typically, the metal(s) at a surface of asupport may constitute from about 0.25% to about 10%, or from about 1%to about 8%, or from about 2.5% to about 7.5% (e.g., 5%) of the totalweight of the catalyst.

In various embodiments, the oxidation catalyst comprises a first metal(M1) and a second metal (M2) at a surface of a support, wherein the M1metal is selected from the group consisting of palladium and platinumand the M2 metal is selected from the group consisting of d-blockmetals, rare earth metals, and main group metals, wherein the M1 metalis not the same metal as the M2 metal. In various preferred embodiments,the M1 metal is platinum and the M2 metal is selected from the groupconsisting of manganese, iron, and cobalt.

The M1:M2 molar ratio may vary, for example, from about 500:1 to about1:1, from about 250:1 to about 1:1, from about 100:1 to about 1:1, fromabout 50:1 to about 1:1, from about 20:1 to about 1:1, or from about10:1 to about 1:1. In various other embodiments, the M1:M2 molar ratiomay vary, for example, from about 1:100 to about 1:1, from about 1:50 toabout 1:1, from about 1:10 to about 1:1, from about 1:5 to about 1:1, orfrom about 1:2 to about 1:1.

Moreover, the weight percents of M1 and M2 relative to the catalystweight may vary. Typically, the weight percent of M1 may range fromabout 0.5% to about 10%, more preferably from about 1% to about 8%, andstill more preferably from about 2.5% to about 7.5% (e.g., about 5%).The weight percent of M2 may range from about 0.25% to about 10%, fromabout 0.5% to about 8%, or from about 0.5% to about 5%.

In various other embodiments, a third metal (M3) may be added to producea M1/M2/M3 catalyst wherein the M3 metal is not the same metal as the M1metal and the M2 metal. In yet other embodiments a fourth metal (M4) maybe added to produce a M1/M2/M3/M4 catalyst wherein the M4 metal is notthe same metal as the M1 metal, the M2 metal or the M3 metal. The M3metal and M4 metal may each be selected from the group consisting ofd-block metals, rare earth metals (e.g. lanthanides), or main groupmetals (e.g. Al, Ga, Tl, In, Sn, Pb or Bi).

Suitable catalyst supports include carbon, alumina, silica, ceria,titania, zirconia, niobia, zeolite, magnesia, clays, iron oxide, siliconcarbide, aluminosilicates, and modifications, mixtures or combinationsthereof. The preferred support materials may be modified using methodsknown in the art such as heat treatment, acid treatment or by theintroduction of a dopant (for example, metal-doped titanias, metal-dopedzirconias (e.g., tungstated-zirconia), metal-doped cerias, andmetal-modified niobias). Particularly preferred supports are carbon(which may be activated carbon, carbon black, coke or charcoal),alumina, zirconia, titania, zeolite and silica. In various embodiments,the support of the oxidation catalyst is selected from the groupconsisting of carbon, zirconia, zeolite, and silica.

When a catalyst support is used, the metals may be deposited usingprocedures known in the art including, but not limited to incipientwetness, ion-exchange, deposition-precipitation, and vacuumimpregnation. When two or more metals are deposited on the same support,they may be deposited sequentially or simultaneously. In variousembodiments, following metal deposition, the catalyst is dried at atemperature of at least about 50° C., more typically at least about 120°C. for a period of time of at least about 1 hour, more typically 3 hoursor more. In these and other embodiments, the catalyst is dried undersub-atmospheric pressure conditions. In various embodiments, thecatalyst is reduced after drying (e.g., by flowing 5% H₂ in N₂ at 350°C. for 3 hours). Still further, in these and other embodiments, thecatalyst is calcined, for example, at a temperature of at least about500° C. for a period of time (e.g., at least about 3 hours).

The reaction product of the oxidation step will, as described above,yield glucaric acid in considerable and heretofore unexpected fraction,but may also yield derivatives thereof, such as glucarolactones. Theseglucarolactones, like glucaric acid, constitute hydrodeoxygenationsubstrate which is particularly amenable to the production of adipicacid product as hereinafter described. Glucarolactones which may bepresent in the reaction mixture resulting from the oxidation stepinclude mono and di-lactones such as D-glucaro-1,4-lactone,D-glucaro-6,3-lactone, and D-glucaro-1,4:6,3-dilactone. One advantage ofhigher concentrations of glucarolactones is further improvement in theeconomics of the hydrodeoxygenation step resulting from a reduction inthe amount of water produced.

Glucaric acid produced in accordance with the above may be converted tovarious other glucaric acid derivatives, such as salts, esters, ketones,and lactones. Methods to convert carboxylic acids to such derivativesare known in the art, see, for example, Wade, Organic Chemistry 3^(rd)ed, Prentice Hall 1995.

III. Preparation of an Adipic Acid Product

In accordance with the present invention, an adipic acid product may beprepared by chemocatalytic conversion of a glucose source. In variousembodiments, preparation of an adipic acid product includeschemocatalytic conversion of a glucose source to glucaric acid. In theseand other embodiments, a hydrodeoxygenation substrate comprising atleast a portion of the glucaric acid or derivatives thereof is convertedto an adipic acid product. Derivatives of glucaric acid includecompounds as defined below.

The hydrodeoxygenation substrate comprises a compound of the formula I:

wherein X is independently hydroxyl, oxo, halo, acyloxy or hydrogenprovided that at least one X is not hydrogen; R¹ is independently asalt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl; ora mono- or di-lactone thereof.

As used herein, the term “hydrocarbyl” refers to hydrocarbyl moieties,preferably containing 1 to about 50 carbon atoms, preferably 1 to about30 carbon atoms, and even more preferably 1 to about 18 carbon atoms,including branched or unbranched, and saturated or unsaturated species.Preferred hydrocarbyl can be selected from the group consisting ofalkyl, alkylene, alkoxy, alkylamino, thioalkyl, haloalkyl, cycloalkyl,cycloalkylalkyl, heterocyclyl, N-heterocyclyl, heterocyclylalkyl, aryl,aralkyl heteroaryl, N-heteroaryl, heteroarylalkyl, and the like. Ahydrocarbyl may be optionally substituted hydrocarbyl. Hence, varioushydrocarbyls can be further selected from substituted alkyl, substitutedcycloalkyl and the like.

Salt forming ions include, without limitation, for example ammonium ionsand metal ions (e.g., alkali and alkaline earth metals). When R¹ is asalt forming ion (i.e., a cation), the carboxyl group may be consideredto be anion (i.e., carboxylate anion).

In various embodiments, the hydrodeoxygenation substrate comprises acompound of formula I, wherein X is hydroxyl and R¹ is independently asalt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl.

As shown in formula I, the hydrodeoxygenation substrate contains a sixcarbon chain comprising four chiral centers. As a result severalstereoisomers are possible. However, the preferred hydrodeoxygenationsubstrate comprises glucaric acid.

The hydrodeoxygenation substrate may also contain various ketones. Forexample, not wishing to be bound by theory, when glucaric acid isfurther oxidized, ketones such as 2-keto-glucaric acid(2,3,4-trihydroxy-5-oxohexanedioic acid) and 3-keto-glucaric acid(2,3,5-trihydroxy-4-oxohexanedioic acid) may be formed.

The hydrodeoxygenation substrate may comprise various lactones derivedfrom glucaric acid. For example, not wishing to be bound by theory, itis believed that various mono- and di-lactones are present inequilibrium with glucaric acid in aqueous solution, including forexample, D-glucaro-1,4-lactone, D-glucaro-6,3-lactone, andD-glucaro-1,4:6,3-dilactone. Moreover, processes have been developed toquantitatively convert glucaric acid or a salt thereof in solution toone or more lactones and recover a substantially pure lactone stream.For example see “Convenient Large-Scale Synthesis ofD-Glucaro-1,4:6,3-dilactone” Gehret et al., J. Org. Chem., 74 (21), pp.8373-8376 (2009). Also, lactones such asL-threo-4-deoxy-hex-4-enaro-6,3-lactone andL-erythro-4-deoxy-hex-4-enaro-6,3-lactone may form from the thermaldecomposition of D-Glucaro-1,4:6,3-dilactone.

Therefore, in various embodiments, the hydrodeoxygenation substratecomprises D-glucaro-1,4-lactone. In these and other embodiments, thehydrodeoxygenation substrate comprises D-glucaro-6,3-lactone. Stillfurther, in these and other embodiments, the hydrodeoxygenationsubstrate comprises D-glucaro-1,4:6,3-dilactone. In these and otherembodiments, the hydrodeoxygenation substrate comprisesL-threo-4-deoxy-hex-4-enaro-6,3-lactone. Still even further, in theseand other embodiments, the hydrodeoxygenation substrate comprisesL-erythro-4-deoxy-hex-4-enaro-6,3-lactone.

Also, in accordance with the present invention, an adipic acid product(formula II) may be prepared by reacting, in the presence of ahydrodeoxygenation catalyst and a halogen source, a hydrodeoxygenationsubstrate (formula I) and hydrogen, according to the following reaction:

wherein X and R¹ are defined as described above.

In preferred embodiments, the adipic acid product (formula II) comprisesadipic acid.

In the above reaction, a hydrodeoxygenation substrate is converted to anadipic acid product by catalytic hydrodeoxygenation in whichcarbon-hydroxyl groups are converted to carbon-hydrogen groups. Invarious embodiments, the catalytic hydrodeoxygenation ishydroxyl-selective wherein the reaction is completed without substantialconversion of the one or more other non-hydroxyl functional group of thesubstrate.

In accordance with the present invention, a hydrodeoxygenation substrateis catalytically hydrodeoxygenated in the presence of hydrogen, ahalogen source and a hydrodeoxygenation catalyst. Without being bound bytheory, it is believed that during this reaction the hydrodeoxygenationsubstrate is halogenated with the halogen source, to form a halogenatedintermediate containing a carbon-halogen bond (e.g., a secondary alcoholgroup on the glucaric acid is converted to a halide to produce an alkylhalide). The carbon-halogen bond of the halogenated intermediate isbelieved to be converted to a carbon-hydrogen bond via one or more ofthe following pathways. In the first pathway, the halogenatedintermediate reacts with hydrogen in the presence of thehydrodeoxygenation catalyst leading to the formation of acarbon-hydrogen bond along with the generation of hydrohalic acid. Inthe second pathway, the halogenated intermediate undergoes adehydrohalogenation reaction to form an olefin intermediate andhydrohalic acid. The olefin is further reduced in the presence of thehydrodeoxygenation catalyst leading to the formation of acarbon-hydrogen bond (or the olefin may be an enol form of a ketonewhich can interconvert to a keto form which can reduce to an alcoholgroup which can undergo further hydrodeoxygenation). Effecting thereaction pursuant to the above described first and second pathwaysgenerates hydrohalic acid as a by-product, which is available forfurther reaction. In the third pathway, the halogenated intermediatereacts with hydrohalic acid leading to the formation of acarbon-hydrogen bond along with the formation of molecular halogen (orinterhalogen). Effecting the reaction pursuant to the third pathwaygenerates molecular halogen as a by-product, which is available forfurther reaction. One or more of the various pathways described abovemay occur concurrently.

It should be recognized that the hydrodeoxygenation reaction can beconducted by first forming and optionally purifying or isolating thesevarious intermediates formed by combining a hydrodeoxygenation substrateand a halogen source and subsequently reacting the intermediate withhydrogen in the presence of the hydrodeoxygenation catalyst andoptionally in the absence of any halogen source.

In various embodiments, the hydrodeoxygenation substrate is halogenatedwith hydrohalic acid to form a halogenated intermediate (e.g., an alkylhalide). In other embodiments, the hydrodeoxygenation substrate ishalogenated with a molecular halogen to form the halogenatedintermediate (e.g., an alkyl halide).

The halogen source may be in a form selected from the group consistingof atomic, ionic, molecular, and mixtures thereof. Halogen sourcesinclude hydrohalic acids (e.g., HCl, HBr, HI and mixtures thereof;preferably HBr and/or HI), halide salts, (substituted or unsubstituted)alkyl halides, or elemental halogens (e.g. chlorine, bromine, iodine ormixtures thereof preferably bromine and/or iodine). In variousembodiments the halogen source is in molecular form and, morepreferably, is bromine. In more preferred embodiments, the halogensource is a hydrohalic acid, in particular hydrogen bromide.

Generally, the molar ratio of halogen to the hydrodeoxygenationsubstrate is about equal to or less than about 1. In variousembodiments, the mole ratio of halogen to the hydrodeoxygenationsubstrate is typically from about 1:1 to about 0.1:1, more typicallyfrom about 0.7:1 to about 0.3:1, and still more typically about 0.5:1.

Generally, the reaction allows for recovery of the halogen source andcatalytic quantities (where molar ratio of halogen to thehydrodeoxygenation substrate is less than about 1) of halogen can beused, recovered and recycled for continued use as a halogen source.

Generally, the temperature of the hydrodeoxygenation reaction mixture isat least about 20° C., typically at least about 80° C., and moretypically at least about 100° C. In various embodiments, the temperatureof the hydrodeoxygenation reaction is conducted in the range of fromabout 20° C. to about 250° C., from about 80° C. to about 200° C., morepreferably from about 120° C. to about 180° C., and still morepreferably between about 140° C. and 180° C.

Typically, the partial pressure of hydrogen is at least about 25 psia(172 kPa), more typically at least about 200 psia (1379 kPa) or at leastabout 400 psia (2758 kPa). In various embodiments, the partial pressureof hydrogen is from about 25 psia (172 kPa) to about 2500 psia (17237kPa), from about 200 psia (1379 kPa) to about 2000 psia (13790 kPa), orfrom about 400 psia (2758 kPa) to about 1500 psia (10343 kPa).

The hydrodeoxygenation reaction is typically conducted in the presenceof a solvent. Solvents suitable for the selective hydrodeoxygenationreaction include water and carboxylic acids, amides, esters, lactones,sulfoxides, sulfones and mixtures thereof. Preferred solvents includewater, mixtures of water and weak carboxylic acid, and weak carboxylicacid. A preferred weak carboxylic acid is acetic acid.

In general, the reaction can be conducted in a batch, semi-batch, orcontinuous reactor design using fixed bed reactors, trickle bedreactors, slurry phase reactors, moving bed reactors, or any otherdesign that allows for heterogeneous catalytic reactions. Examples ofreactors can be seen in Chemical Process Equipment—Selection and Design,Couper et al., Elsevier 1990, which is incorporated herein by reference.It should be understood that the hydrodeoxygenation substrate, halogensource, hydrogen, any solvent, and the hydrodeoxygenation catalyst maybe introduced into a suitable reactor separately or in variouscombinations.

In various preferred embodiments, the hydrodeoxygenation catalyst isheterogeneous, but a suitable homogeneous catalyst may be employed. Inthese and various other preferred embodiments the hydrodeoxygenationcatalyst comprises a solid-phase heterogeneous catalyst in which one ormore metals is present at a surface of a support (i.e., at one or moresurfaces, external or internal). Preferred metals are d-block metalswhich may be used alone, in combination with each other, in combinationwith one or more rare earth metals (e.g. lanthanides), and incombination with one or more main group metals (e.g., Al, Ga, Tl, In,Sn, Pb or Bi). Preferred d-block metals are selected from the groupconsisting of cobalt, nickel, ruthenium, rhodium, palladium, osmium,iridium, platinum and combinations thereof. More preferred d-blockmetals are selected from the group consisting of ruthenium, rhodium,palladium, platinum, and combinations thereof. In certain preferredembodiments, the catalyst comprises platinum. In general, the metals maybe present in various forms (e.g., elemental, metal oxide, metalhydroxides, metal ions etc.). Typically, the metal(s) at a surface of asupport may constitute from about 0.25% to about 10%, or from about 1%to about 8%, or from about 2.5% to about 7.5% (e.g., 5%) of the catalystweight.

In various embodiments, the catalyst comprises two or more metals. Forexample, two of more metals (M1 and M2) may be co-supported on or withinthe same support (e.g., as a mixed-metal catalyst on silica;M1/M2/Silica catalyst), or they may be supported on different supportmaterials. In various embodiments the hydrodeoxygenation catalystcomprises a first metal (M1) and a second metal (M2) at a surface of asupport, wherein the M1 metal comprises a d-block metal and the M2 metalis selected from the group consisting of d-block metals, rare earthmetals, and main group metals, wherein the M1 metal is not the samemetal as the M2 metal. In various embodiments, the M1 metal is selectedfrom the group consisting of cobalt, nickel, ruthenium, rhodium,palladium, osmium, iridium, and platinum. In more preferred embodiments,the M1 metal is selected from the group consisting of ruthenium,rhodium, palladium, and platinum. In various embodiments, the M2 metalis selected from the group consisting of titanium, vanadium, chromium,manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium,palladium, silver, tungsten, iridium, platinum, and gold. In morepreferred embodiments, the M2 metal is selected from the groupconsisting of molybdenum, ruthenium, rhodium, palladium, iridium,platinum, and gold.

In more preferred embodiments, the M1 metal is selected from the groupof platinum, rhodium and palladium, and the M2 metal is selected fromthe group consisting of ruthenium, rhodium, palladium, platinum, andgold. In certain more preferred embodiments, M1 is platinum and M2 isrhodium.

In various embodiments, the M1:M2 molar ratio may vary, for example,from about 500:1 to about 1:1, from about 250:1 to about 1:1, from about100:1 to about 1:1, from about 50:1 to about 1:1, from about 20:1 toabout 1:1, or from about 10:1 to about 1:1. In various otherembodiments, the M1:M2 molar ratio may vary, for example, from about1:100 to about 1:1, from about 1:50 to about 1:1, from about 1:10 toabout 1:1, from about 1:5 to about 1:1, or from about 1:2 to about 1:1.

Moreover, in various embodiments, the weight percents of M1 and M2relative to the total catalyst weight may vary. Typically, the weightpercent of M1 may range from about 0.5% to about 10%, more preferablyfrom about 1% to about 8%, and still more preferably from about 2.5% toabout 7.5% (e.g., about 5%). The weight percent of M2 may range fromabout 0.25% to about 10%, from about 0.5% to about 8%, or from about0.5% to about 5%.

In various other embodiments, a third metal (M3) may be added to producea M1/M2/M3 catalyst wherein the M3 metal is not the same metal as the M1metal and the M2 metal. In other embodiments a fourth metal (M4) may beadded to produce a M1/M2/M3/M4 catalyst wherein the M4 metal is not thesame metal as the M1 metal, the M2 metal or the M3 metal. M3 and M4 mayeach be selected from the group consisting of d-block metals, rare earthmetals (e.g. lanthanides), or main group metals (e.g. Al, Ga, Tl, In,Sn, Pb or Bi).

Preferred catalyst supports include carbon, alumina, silica, ceria,titania, zirconia, niobia, zeolite, magnesia, clays, iron oxide, siliconcarbide, aluminosilicates, and modifications, mixtures or combinationsthereof. The preferred supports may be modified through methods known inthe art such as heat treatment, acid treatment, the introduction of adopant (for example, metal-doped titanias, metal-doped zirconias (e.g.tungstated zirconia), metal-doped cerias, and metal-modified niobias).In various preferred embodiments, the hydrodeoxygenation catalystsupport is selected from the group consisting of silica, zirconia andtitania. In certain preferred embodiments, a catalyst comprisingplatinum and rhodium is on a support comprising silica.

When a catalyst support is used, the metals may be deposited usingprocedures known in the art including, but not limited to incipientwetness, ion-exchange, deposition-precipitation and vacuum impregnation.When the two or more metals are deposited on the same support, they maybe deposited sequentially, or simultaneously. In various embodiments,following metal deposition, the catalyst is dried at a temperature of atleast about 50° C., more typically at least about 120° C. or more for aperiod of time of at least about 1 hour, more typically at least about 3hours or more. In these and other embodiments, the catalyst is driedunder sub-atmospheric conditions. In various embodiments, the catalystis reduced after drying (e.g., by flowing 5% H₂ in N₂ at 350° C. for 3hours). Still further, in these and other embodiments, the catalyst iscalcined, for example, at a temperature of at least about 500° C. for aperiod of time (e.g., at least about 3 hours).

Without being bound by theory not expressly recited in the claims,catalysts mixtures (co-catalysts or mixed metal catalysts) containingmore than one metal may affect separate steps of the mechanisticreaction pathway.

An adipic acid product may be recovered from the hydrodeoxygenationreaction mixture by one or more conventional methods known in the artincluding, for example, solvent extraction, crystallization orevaporative processes.

IV. Downstream Chemical Products

Various methods are known in the art for conversion of adipic acid todownstream chemical products or intermediates including adipate esters,polyesters, adiponitrile, hexamethylene diamine (HMDA), caprolactam,caprolactone, 1,6-hexanediol, aminocaproic acid, and polyamide such asnylons. For conversions from adipic acid, see for example, withoutlimitation, U.S. Pat. Nos. 3,671,566, 3,917,707, 4,767,856, 5,900,511,5,986,127, 6,008,418, 6,087,296, 6,147,208, 6,462,220, 6,521,779,6,569,802, and Musser, “Adipic Acid” in Ullmann's Encyclopedia ofIndustrial Chemistry, Wiley-VCH, Weinheim, 2005.

In various embodiments, an adipic acid product is converted toadiponitrile wherein the adipic acid product is prepared in accordancewith the present invention. Adiponitrile can be used industrially forthe manufacture of hexamethylene diamine, see Smiley,“Hexamethylenediamine” in Ullman's Encyclopedia of Industrial Chemistry,Wiley-VCH 2009. Therefore, in further embodiments, an adipic acidproduct is converted to hexamethylene diamine wherein the adipic acidproduct is prepared in accordance with the present invention.

Adipic acid is useful in the production of polyamides, such as nylon 6,6and nylon 4,6. See, for example, U.S. Pat. No. 4,722,997, and Musser,“Adipic Acid” in Ullmann's Encyclopedia of Industrial Chemistry,Wiley-VCH, Weinheim, 2005. The hexamethylene diamine formed from anadipic acid product prepared in accordance with the present inventioncan likewise be further used for the preparation of polyamides such asnylon 6,6 and nylon 6,12. See, for example Kohan, Mestemacher,Pagilagan, Redmond, “Polyamides” in Ullmann's Encyclopedia of IndustrialChemistry, Wiley-VCH, Weinheim, 2005.

Accordingly, adipic acid and a polymer precursor derived from an adipicacid product (e.g., hexamethylene diamine) may be reacted to produce apolyamide, wherein the adipic acid product is prepared in accordancewith the present invention. Polymer precursor, as used herein, refers toa monomer which can be converted to a polymer (or copolymer) underappropriate polymerization conditions. In various embodiments, thepolyamide comprises nylon 6,6. In these embodiments, nylon 6,6 isproduced by reacting an adipic acid product with a polymer precursorderived from an adipic acid product, wherein the polymer precursorcomprises hexamethylene diamine. In these embodiments, hexamethylenediamine may be prepared by converting an adipic acid product toadiponitrile which then may be converted to hexamethylene diamine,wherein the adipic acid product is prepared in accordance with thepresent invention.

In other embodiments, an adipic acid product is converted to caprolactamwherein the adipic acid product is prepared in accordance with thepresent invention. The caprolactam formed can be further used for thepreparation of polyamides by means generally known in the art.Specifically, caprolactam can be further used for the preparation ofnylon 6. See, for example Kohan, Mestemacher, Pagilagan, Redmond,“Polyamides” in Ullmann's Encyclopedia of Industrial Chemistry,Wiley-VCH, Weinheim, 2005.

In various embodiments, nylon 6 is produced by reacting caprolactamderived from an adipic acid product prepared in accordance with thepresent invention.

In other embodiments, adipic acid and a polymer precursor may be reactedto produce a polyester, wherein the adipic acid product is prepared inaccordance with the present invention.

In other embodiments, an adipic acid product is converted to1,6-hexanediol wherein the adipic acid product is prepared in accordancewith the present invention. 1,6-hexanediol is a valuable chemicalintermediate used in the production of polyesters and polyurethanes.Accordingly, in various embodiments, polyester may be prepared byreacting adipic acid and 1,6-hexandiol derived from an adipic acidproduct, prepared in accordance with the present invention.

In various embodiments a salt of adipic acid may be produce wherein theprocess comprises reacting adipic acid with hexamethylene diamine,thereby forming the salt, wherein adipic acid is prepared in accordancewith the present invention.

When introducing elements of the present invention or the preferredembodiments(s) thereof, the articles “a”, “an”, “the” and “said” areintended to mean that there are one or more of the elements. The terms“comprising”, “including” and “having” are intended to be inclusive andmean that there may be additional elements other than the listedelements.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above compositions and processeswithout departing from the scope of the invention, it is intended thatall matter contained in the above description shall be interpreted asillustrative and not in a limiting sense.

Having described the invention in detail, it will be apparent thatmodifications and variations are possible without departing from thescope of the invention defined in the appended claims.

EXAMPLES

The following non-limiting examples are provided to further illustratethe present invention.

Reactions were conducted in 1 mL glass vials housed in a pressurizedvessel in accordance with the procedures described in the examplesbelow. Product yields were determined using a Dionex ICS-3000Chromatography system. For Example 1, the products were first separatedon an Ionpac© AS11-HC column and then quantified by conductivitydetection through comparison with calibration standards. For Example 2,the products were first separated on an Acclaim© Organic Acid column andthen quantified by a UV detector through comparison with calibrationstandards.

Example 1 Glucose to Glucaric Acid

Several catalysts were obtained from commercial vendors: Johnson Matthey5% Pt/C (three examples; JM-23 [B103032-5, Lot #C-9090]; JM-25[B103014-5, Lot #C9230]; and JM-27 [B-501032-5, Lot #C-9188]), JohnsonMatthey 5% Pt/Al₂O₃ (two examples; JM-32 [B301013-5, Lot #C8959] andJM-33 [B301099-5, Lot #C9218]), and BASF Escat 2351 5% Pt/SiO₂ [Lot#A4048107]; and 1.5% Au/TiO₂ [Süd Chemie 02-10]. Other catalysts wereprepared in accordance with the procedure described herein.

Preparation of Supported Platinum Catalysts

Multiple portions of suitably concentrated aqueous Pt(NO₃)₂ solutions(Heraeus) were added to the appropriate support (wherein the totalcombined volume of the Pt(NO₃)₂ solutions was matched to equal to thepore volume of the chosen support) with agitation between additions.Post impregnation, the product was dried in a furnace at 120° C. for 12hours, Material for catalyst testing was prepared by reduction underflowing 5 vol. % H₂ in N₂ for 3 hours at either 200° C. or 350° C. Notethat this procedure was used for all supports except carbon. See thelater description for the preparation of a Pt/Carbon catalyst.

Preparation of Pt/M2/Support Catalysts (M2=Mn, Co, Fe, Re, Cu)

Approximately 7-8 mg of dried supported platinum catalyst (taken postdrying but prior to reduction) was dispensed into an 8×12 arraycontaining 1 mL glass vials. To select vials within the array, 6-7 μl(where the total addition volume was matched to equal to the pore volumeof the support weighed into the vial) of suitably concentrated M2 stocksolutions were added (M2=Mn, Fe, Co, Re, Cu obtained from Strem orSigma-Aldrich, see Table 1). Post M2 addition, the mixtures wereagitated via a multi-tube vortexer to impregnate the supports. Postimpregnation, the glass vial arrays of Pt/M2/Support catalysts weredried in a furnace at 120° C. for 1 hour, followed by calcination at500° C. for 3 hours followed by reduction under flowing 5 vol. % H₂ inN₂ at either 200° C. or 350° C. for 3 hours. Note that this procedurewas used to prepare all Pt/M2/Support catalysts with the exception ofthe 1.5% Pt/1.5% Au/Titania catalyst. In this case Pt(NO₃)₂ solution wasadded to a dried sample of the commercial 1.5% Au/Titania catalyst [SüdChemie 02-10] (wherein the total volume of the Pt(NO₃)₂ volume wasmatched to equal to the pore volume of the catalyst) with agitation,whereupon the material was dried in a furnace at 120° C. for 1 hour,followed by reduction under flowing 5 vol. % H₂ in N₂ at 350° C. for 3hours.

Preparation of 4 wt. % Pt/Carbon Catalyst

Multiple portions of suitably concentrated aqueous Pt(NO₃)₂ solution(Heraeus) were added to 2 g of dried Degussa HP-160 furnace black carbon(3.94 mL total addition volume) with agitation between additions. Postimpregnation, the 4 wt. % Pt/Carbon was dried under vacuum for one hourat 50° C., followed by reduction under flowing 5 vol. % H₂ in N₂ forthree hours at 350° C.

Glucose to Glucaric Acid Reactions

Catalysts were dispensed into 1 mL vials within a 96-well reactor insert(Symyx Solutions). The reaction substrate was D-glucose (Sigma-Aldrich,0.552M in water). To each vial was added 250 μL of glucose solution. Thevials were each covered with a Teflon pin-hole sheet, a siliconepin-hole mat and steel gas diffusion plate (Symyx Solutions). Thereactor insert was placed in a pressure vessel and charged three timeswith oxygen to 100 psig with venting after each pressurization step. Thereactor was then charged to 75 psig with oxygen, or to 500 psig withair, closed and placed on a shaker, heated at the designated temperaturefor the specified reaction time. After the reaction time had elapsedshaking was stopped and the reactor cooled to room temperature whereuponthe reactors were vented. Samples for ion-chromatography (IC) analysiswere prepared by adding to each reaction vial 750 μL of a 1.067 wt. %citric acid solution (as internal standard) then the plate was coveredand mixed followed by centrifugation to separate catalyst particles.Each reaction sample was further diluted by performing two 20-folddilutions then analyzed by Ion Chromatography. In some instances, HClwas used as alternative internal standard through the addition of 100 μLof 50 ppm solution during the second 20-fold dilution. The results arepresented in Table 1.

TABLE 1 Catalyst Glucaric M1 Temp. Time Amount Acid Yield Catalyst (wt.% M2 wt. % Pt/Support) Precursor M2 Precursor (° C.) (Hours) (mg) (%) 10.06% Mn 4% Pt/Silica Davisil 635 Pt(NO₃)₂ Mn(NO₃)₂ 80 5 7 38 2 0.06% Fe4% Pt/Silica Davisil 635 Pt(NO₃)₂ Fe(NO₃)₃ 80 5 8 28 3 0.06% Co 4%Pt/Silica Davisil 635 Pt(NO₃)₂ Co(NO₃)₂ 80 5 8 34 4 4% Pt/Silica Davisil635 Pt(NO₃)₂ None 80 5 8 34 5 4% Pt/Silica 5 μm Cariact Pt(NO₃)₂ None 905 8 50 6 4% Pt/Silica 5 μm Cariact Pt(NO₃)₂ None 90 8 8 66 7 4%Pt/Silica Merck 10180 Pt(NO₃)₂ None 90 5 8 40 8 1.91% Re 4% Pt/SilicaMerck 10180 Pt(NO₃)₂ HReO₄ 90 5 8 39 9 0.65% Cu 4% Pt/Silica Merck 10180Pt(NO₃)₂ Cu(NO₃)₂ 90 5 8 39 10 0.10% Mo 4% Pt/Silica Merck 10180Pt(NO₃)₂ (NH₄)₆Mo₇O₂₄ 90 5 8 38 11 4% Pt/Carbon Degussa HP-160 Pt(NO₃)₂None 80 5 8 53 12 4% Pt/Carbon Degussa HP-160 Pt(NO₃)₂ None 90 8 8 60 135% Pt/C [JM-23] None 80 5 10 52 14 5% Pt/C [JM-25] None 80 5 10 57 15 5%Pt/C [JM-27] None 80 5 10 57 16 5% Pt/Al₂O₃ [JM-32] None 80 5 10 23 175% Pt/Al₂O₃ [JM-33] None 80 5 10 31 18 5% Pt/SiO₂ [BASF Escat 2351]Pt(NO₃)₂ None 80 5 10 15 19 8% Pt/Zirconia Daiichi Kigenso Z-1044Pt(NO₃)₂ None 90 5 8 52 20 8% Pt/Zirconia Daiichi Kigenso Z-1628Pt(NO₃)₂ None 90 5 8 59 21 8% Pt/Zirconia Ceria Daiichi Kigenso Z-1006Pt(NO₃)₂ None 90 5 8 54 22 8% Pt/Ceria Daiichi Kigenso Z-1627 Pt(NO₃)₂None 90 5 8 17 ^(b)23 ^(a)4% Pt/Zeolite Zeolyst CP 811C-300 Pt(NO₃)₂None 100 5 8 39 ^(b)24 ^(a)4% Pt/Titania NorPro ST 61120 Pt(NO₃)₂ None100 5 8 30 ^(b)24 1.5% Pt 1.5% Au/Titania [Süd Chemie 02-10] Pt(NO₃)₂100 5 8 55 ^(b)25 4% Pt 4% Au/Titania NorPro ST 61120 AuCl₃ Pt(NO₃)₂ 1005 8 32 ^(a)These catalysts were calcined at 500° C. for 3 hours prior toreduction. ^(b)These reactions were run under 500 psig of air, all otherreactions in Table 1 were run under 75 psig of O₂. Catalysts in examples4-7, 11-12 were reduced at 200° C. under flowing 5 vol. % H₂ in N₂ for 3hours. Catalysts in examples 1-3, 8-10, 19-25 were reduced at 350° C.under flowing 5 vol. % H₂ in N₂ for 3 hours. Commercial catalysts inexamples 13-18 were screened directly.

Example 2 Glucaric Acid to Apidic Acid

Preparation of M1/Support Catalysts (M1=Ru, Rh, Pd, Pt)x

2 g of dried 5 μm Silica Cariact (Fuji Silysia) or 45 μm Titania NorProST 61120 (Saint-Gobain) was weighed into vials. Suitably concentrated M1stock solutions (M1=Ru, Rh, Pd, Pt) were prepared from concentratedacidic stock solutions purchased from Heraeus (see Table 1). For eachM1, multiple additions of the dilute M1 stock solution were added to theSupport (Silica pore volume=0.7 mL/g, Titania NorPro=0.45 mL/g) until atotal volume of 1.4 ml (Silica) or 0.9 mL (Titania) was reached. Aftereach addition, the mixtures were agitated to impregnate the support.Post impregnation, the X wt. % M1/Support mixtures (X=2-5) were dried ina furnace at 120° C. for 12 hours.

Preparation of M1/M2/Support Catalysts (M2=Ru, Rh, Pd, Ir, Pt, Au, Mo)

7-12 mg of dried X wt. % M1/Support (M1=Ru, Rh, Pd Pt) (X=2-5) weredispensed into 8×12 arrays containing 1 mL glass vials. To select vialswithin the array, 3-8 μl (where the total addition volume was matched toequal to the pore volume of the dried X wt. % M1/Support catalystsweighed into the vial) of suitably concentrated M2 stock solutions wereadded (M2=Ru, Rh, Pd, Ir, Pt, Au (obtained from Heraeus), and Mo(obtained from Strem), see Table 1). Post M2 addition, the mixtures wereagitated via a multi-tube vortexer to impregnate the supports. Postimpregnation, the glass vial arrays of M1/M2/Support catalysts weredried in a furnace at 120° C. for 1 hour, followed by calcination at500° C. for 3 hours. Upon cooling the arrays of catalysts were stored ina dessicator until used.

Preparation of M1/M2/Support Catalysts by Coimpregnation (M1/M2=Rh, Pd,Pt).

7-12 mg of silica support (Davisil 635 W.R. Grace & Co.) were dispensedinto 8×12 arrays containing 1 mL glass vials. Supports were dried at120° C. for 12 hours prior to use. To select vials within the array,6-11 μl (where the total addition volume was matched to equal to thepore volume of the Support weighed into the vial) of suitablyconcentrated pre-mixed M1/M2 stock solutions were added (M1/M2=Rh, Pd,Pt) (obtained from Heraeus), Post metal addition, the mixtures wereagitated via a multi-tube vortexer to impregnate the supports. Postimpregnation, the glass vial arrays of M1/M2/Support catalysts weredried in a furnace at 120° C. for 1 hour, followed by calcination at500° C. for 3 hours. Upon cooling the arrays of catalysts were stored ina dessicator until used.

Glucaric Acid to Adipic Acid Reactions.

The arrays of catalysts were transferred to 1 mL glass vials within a96-well reactor insert (Symyx Solutions). Each vial within each arrayreceived a glass bead and 250 μL of 0.2 M Glucaric Acid (prepared fromcalcium glucarate) (Sigma-Adrich), 0.1 M HBr (examples 1-37;Sigma-Aldrich) or 0.2 M HBr (example 38; Sigma-Aldrich) in Acetic Acid(Sigma-Aldrich). Upon solution addition, the arrays of vials werecovered with a Teflon pin-hole sheet, a silicone pin-hole mat and steelgas diffusion plate (Symyx Solutions). The reactor insert was placed ina pressure vessel pressurized and vented 3 times with nitrogen and 3times with hydrogen before being pressurized with hydrogen to 710 psig,heated to 140° C. (examples 1-37) or 160° C. (example 38) and shaken for3 hours. After 3 hours the reactors were cooled, vented and purged withnitrogen. 750 μl of water was then added to each vial. Following thewater addition, the arrays were covered and shaken to ensure adequatemixing. Subsequently, the covered arrays were placed in a centrifuge toseparate the catalyst particles. Each reaction samples was then diluted2-fold with water to generate a sample for analysis by HPLC. The resultsare presented in Table 2.

TABLE 2 Catalyst Adipic Amount Acid Yield Catalyst (wt. % M2 wt. %M1/Support) M1 Precursor M2 Precursor (mg) (%) 1 0.5% Pd 5% Rh/Silica 5μm Cariact Rh(NO₃)₃ Pd(NO₃)₂ 8 51 2 0.5% Pd 5% Rh/Silica 5 μm CariactRh(NO₃)₃ Pd(NO₃)₂ 8 53 3 0.5% Ru 5% Pd/Silica 5 μm Cariact Pd(NO₃)₂^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 74 4 0.5% Ru 5% Pd/Silica 5 μm CariactPd(NO₃)₂ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 77 5 0.5% Ru 5% Rh/Silica 5 μmCariact Rh(NO₃)₃ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 10 50 6 0.5% Ru 5%Rh/Silica 5 μm Cariact Rh(NO₃)₃ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 57 7 1% Ir5% Rh/Silica 5 μm Cariact Rh(NO₃)₃ H₂IrCl₆•H₂0 8 53 8 2.5% Mo 5%Pd/Silica 5 μm Cariact Pd(NO₃)₂ (NH₄)₆Mo₇O₂₄ 8 53 9 2.5% Pd 5% Rh/Silica5 μm Cariact Rh(NO₃)₃ Pd(NO₃)₂ 8 50 10 2.5% Pd 5% Rh/Silica 5 μm CariactRh(NO₃)₃ Pd(NO₃)₂ 13 50 11 2.5% Ru 5% Pd/Silica 5 μm Cariact Pd(NO₃)₂^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 63 12 2.5% Ru 5% Pd/Silica 5 μm CariactPd(NO₃)₂ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 63 13 2.5% Ru 5% Rh/Silica 5 μmCariact Rh(NO₃)₃ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 11 51 14 2.5% Ru 5%Rh/Silica 5 μm Cariact Rh(NO₃)₃ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 54 15 5%Ir 5% Rh/Silica 5 μm Cariact Rh(NO₃)₃ H₂IrCl₆•H₂0 8 52 16 5% Pt 5%Pd/Silica 5 μm Cariact Pd(NO₃)₂ Pt(NO₃)₂ 8 54 17 ^(b)5% Rh/Silica 5 μmCariact Rh(NO₃)₃ None 8 49 18 ^(b)5% Pd/Silica 5 μm Cariact Pd(NO₃)₂None 8 47 ^(d)19 ^(b)5% Pt/Silica 5 μm Cariact Pt(NO₃)₂ None 8 69 200.5% Au 5% Rh/Silica 5 μm Cariact Rh(NO₃)₃ AuCl₃ 9 48 21 0.5% Au 5%Rh/Silica 5 μm Cariact Rh(NO₃)₃ AuCl₃ 14 50 22 2% Pd 2% Rh/TitaniaNorPro ST 61120 Rh(NO₃)₃ Pd(NO₃)₂ 8 47 23 2% Pd 4% Pt/Titania NorPro ST61120 Pt(NO₃)₂ Pd(NO₃)₂ 7 38 24 4% Pt 2% Ru/Titania NorPro ST 61120^(a)Ru(NO)(NO₃)_(x)(OH)_(y) Pt(NO₃)₂ 9 46 25 4% Pt 2% Rh/Titania NorProST 61120 Rh(NO₃)₃ Pt(NO₃)₂ 8 60 26 4% Pt 2% Pd/Titania NorPro ST 61120Pd(NO₃)₂ Pt(NO₃)₂ 7 39 27 2% Ru 2% Pd/Titania NorPro ST61120 Pd(NO₃)₂^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 12 22 28 2% Ru 4% Pt/Titania NorPro ST 61120Pt(NO₃)₂ ^(a)Ru(NO)(NO₃)_(x)(OH)_(y) 8 38 29 2% Rh 2% Pd/Titania NorProST61120 Pd(NO₃)₂ Rh(NO₃)₃ 7 46 30 2% Rh 4% Pt/Titania NorPro ST 61120Pt(NO₃)₂ Rh(NO₃)₃ 9 52 31 ^(c)1.6% Rh 1.6% Pd/Silica Davisil 635Pd(NO₃)₂ Rh(NO₃)₃ 8 51 32 ^(c)1.6% Rh 3.0% Pt/Silica Davisil 635Pt(NO₃)₂ Rh(NO₃)₃ 8 61 33 ^(c)0.3% Rh 5.4% Pt/Silica Davisil 635Pt(NO₃)₂ Rh(NO₃)₃ 8 47 34 ^(b)3.2% Pd/Silica Davisil 635 Pd(NO₃)₂ none 846 35 ^(b)6.0% Pt/Silica Davisil 635 Pt(NO₃)₂ none 8 35 36 ^(b)3.2%Rh/Silica Davisil 635 Rh(NO₃)₃ none 8 30 37 ^(c)0.6% Pt 2.9% Pt/SilicaDavisil 635 Pd(NO₃)₂ Pt(NO₃)₂ 8 45 ^(e)38 ^(c)1.65% Rh 4.7% Pt/SilicaDavisil 635 Pt(NO₃)₂ Rh(NO₃)₃ 8 89 ^(a)Where x + y = 3 ^(b)Where no M2was used, the M1/Support catalyst was calcined at 500° C. for 3 hoursprior to use ^(c)Prepared by coimpregnation ^(d)This reaction was runfor 6 hours ^(e)This reaction was conducted at 160° C.

What is claimed is:
 1. A process for preparing an adipic acid product,the process comprising: reacting, in the presence of ahydrodeoxygenation catalyst and a halogen source, a hydrodeoxygenationsubstrate and hydrogen gas to convert at least a portion of thehydrodeoxygenation substrate to an adipic acid product, wherein thehydrodeoxygenation substrate comprises a compound of formula I

wherein X is independently hydroxyl, oxo, halo, acyloxy or hydrogenprovided that at least one X is not hydrogen and R¹ is independently asalt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl; ora mono- or di-lactone thereof and wherein the adipic acid product is acompound of formula II

wherein R¹ is as defined for formula I.
 2. The process as set forth inclaim 1 wherein the hydrodeoxygenation substrate comprises a compound offormula I, wherein X is hydroxyl and R¹ is independently a salt-formingion, hydrogen, hydrocarbyl, or substituted hydrocarbyl.
 3. The processas set forth in claim 1 wherein the hydrodeoxygenation substratecomprises glucaric acid.
 4. The process as set forth in claim 1 whereinthe adipic acid product comprises adipic acid.
 5. The process as setforth in claim 1 wherein at least a portion of the hydrodeoxygenationsubstrate is solubilized with a weak carboxylic acid.
 6. The process asset forth in claim 5 wherein the pKa of the weak carboxylic acid is atleast about 4.5.
 7. The process as set forth in claim 1 wherein thehydrodeoxygenation catalyst comprises a heterogeneous catalyst.
 8. Theprocess as set forth in claim 7 wherein the hydrodeoxygenation catalystcomprises at least one d-block metal at a surface of a support.
 9. Theprocess as set forth in claim 8 wherein the d-block metal is selectedfrom the group consisting of Ru, Rh, Pd, Pt, and combinations thereof.10. The process as set forth in claim 7 wherein the hydrodeoxygenationcatalyst comprises a first metal and a second metal, wherein the firstmetal is selected from the group consisting of Ru, Rh, Pd, Pt, andcombinations thereof, and the second metal is selected from the groupconsisting of Mo, Ru, Rh, Pd, Ir, Pt, and Au, and wherein the secondmetal is not the same as the first metal.
 11. The process as set forthin claim 9 wherein the hydrodeoxygenation catalyst support is selectedfrom the group consisting of carbon, silica and zirconia.
 12. Theprocess as set forth in claim 5 wherein the halogen source comprises anionic, atomic, and/or a molecular form of bromine.
 13. The process asset forth in claim 12 wherein the halogen source comprises hydrogenbromide.
 14. The process as set forth in claim 3 wherein the molar ratioof halogen source to hydrodeoxygenation substrate is equal to or lessthan about
 1. 15. The process as set forth in claim 1 wherein thereaction mixture is maintained at a temperature of at least about 80° C.16. The process as set forth in claim 1 wherein the temperature of thereaction mixture is from about 100° C. to about 200° C.
 17. The processas set forth in claim 1 wherein the reaction is conducted under apartial pressure of hydrogen ranging from about 25 psia (172 kPa) toabout 2500 psia (17237 kPa).
 18. The process as set forth in claim 1wherein the hydrodeoxygenation substrate of formula I is prepared byreacting glucose with oxygen to convert at least a portion of theglucose to the hydrodeoxygenation substrate of formula I.
 19. Theprocess of claim 12 wherein the hydrodeoxygenation catalyst comprises Ptand Rh on a support comprising silica.
 20. The process of claim 12wherein the reaction is conducted at a temperature of at least about140° C.
 21. The process of claim 1 wherein the hydrodeoxygenationsubstrate comprises glucaric acid, the hydrodeoxygenation catalystcomprises a heterogeneous catalyst comprising at least one d-block metalselected from the group consisting of Ru, Rh, Pd, Pt, and combinationsthereof at a surface of a support, and the halogen source comprises anionic, atomic, and/or a molecular form of bromine.
 22. The process ofclaim 5 wherein the hydrodeoxygenation substrate comprises glucaricacid, the hydrodeoxygenation catalyst comprises a heterogeneous catalystcomprising at least one d-block metal selected from the group consistingof Ru, Rh, Pd, Pt, and combinations thereof at a surface of a support,and the halogen source comprises an ionic, atomic, and/or a molecularform of bromine.
 23. The process of claim 1 wherein at least a portionof the hydrodeoxygenation substrate is solubilized with a weakcarboxylic acid, the hydrodeoxygenation catalyst comprises aheterogeneous catalyst comprising at least one d-block metal selectedfrom the group consisting of Ru, Rh, Pd, Pt, and combinations thereof ata surface of a support, and the halogen source comprises an ionic,atomic, and/or a molecular form of bromine.
 24. The process of claim 23wherein the hydrodeoxygenation substrate comprises glucaric acid. 25.The process of claim 1 wherein at least a portion of thehydrodeoxygenation substrate is solubilized with a weak carboxylic acid,the hydrodeoxygenation catalyst comprises a heterogeneous catalystcomprising at least one d-block metal selected from the group consistingof Ru, Rh, Pd, Pt, and combinations thereof at a surface of a support,and the halogen source comprises hydrogen bromide.
 26. The process ofclaim 25 wherein the hydrodeoxygenation substrate comprises glucaricacid.
 27. The process as set forth in claim 1 wherein the halogen sourcecomprises an ionic, atomic, and/or a molecular form of bromine.
 28. Theprocess as set forth in claim 3 wherein the adipic acid productcomprises adipic acid.
 29. The process as set forth in claim 24 whereinthe adipic acid product comprises adipic acid.
 30. The process as setforth in claim 6 wherein the halogen source comprises an ionic, atomic,and/or a molecular form of bromine.
 31. The process as set forth inclaim 1 wherein the temperature of the reaction mixture is from about100° C. to about 200° C. and wherein the reaction is conducted under apartial pressure of hydrogen ranging from about 25 psia (172 kPa) toabout 2500 psia (17237 kPa).
 32. The process as set forth in claim 26wherein the temperature of the reaction mixture is from about 100° C. toabout 200° C. and wherein the reaction is conducted under a partialpressure of hydrogen ranging from about 25 psia (172 kPa) to about 2500psia (17237 kPa).
 33. The process as set forth in claim 23 wherein thepKa of the weak carboxylic acid is at least about 4.5.
 34. The processas set forth in claim 26 wherein the pKa of the weak carboxylic acid isat least about 4.5.
 35. The process of claim 19 wherein the reaction isconducted at a temperature of at least about 140° C.
 36. The process ofclaim 18 wherein at least a portion of the glucose and thehydrodeoxygenation substrate of formula I are solubilized with a weakcarboxylic acid.
 37. The process of claim 18 wherein glucose is reactedwith oxygen in the presence of an oxidation catalyst.
 38. The process ofclaim 18 wherein glucose is reacted with oxygen in the substantialabsence of added base.
 39. The process as set forth in claim 36 whereinthe weak carboxylic acid comprises acetic acid.
 40. The process as setforth in claim 36 wherein the pKa of the weak carboxylic acid is atleast about 4.5.